Gun barrel liner



F. D. COTTERMAN GUN BARREL LINER Filed Sept. 30. 1954 Sept. 2, 1958 GUNBARREL LINER Frank D. Cotter-man, Lagrange, Ind., assignor to Crane Co.,Chicago, 111., a corporation of Illinois Application September 30, 1954,Serial No. 459,402

Claims. (Cl. 89-16) This invention relates to improvements in a gunbarrel or the like, and, more particularly, it is concerned with a novelliner therefor.

Heretofore, in connection with the manufacture of gun barrels of certainspecial material-s, for example, it has been diflicult to obtain suchspecial materials in the form required for best performance in ultimateuse. Specifically, for example, it has been relatively diflicult andcostly to obtain a molybdenum barrel made integrally with the usualrifling required. Similarly, the construction of an inner linerintegrally made and formed of molybdenum or other special materials hasalso been diflicult and relatively costly.

Therefore, it is one of the more important objects of this invention toprovide a gun liner formed from a series of identical washers stampedfrom desired sheet material, and which are assembled and accuratelyaligned axially, with the lands and the grooves formed comprising therifling formed in each washer preferably during the stamping operation.

Other objects and advantages of the invention will become more readilyapparent upon proceeding with the description of a preferred form of thedevice read in light of the accompanying drawings, in which Fig. 1 is afragmentary sectional assembly view of the breach end of a gun barrelembodying my invention.

Fig. 2 is a fragmentary sectional assembly view of the forward end of agun barrel embodying my invention.

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a plan view of a preferred form of washer.

Fig. 6 is a transverse sectional assembly view employing a modified formof washer.

Fig. 7 is a plan view of a modified form of washer.

Similar reference numerals refer to similar parts throughout the severalviews.

Referring to the drawings, particularly Fig. 1, the gun barrel generallydesignated 1 is shown having at the breach end 2 a suitable bushing 3threadedly attached thereto as at 4 and apertured as at 5 with the usualreceiving end portion 6 which may be suitably formed as determined bythe nature -of the service for which the gun barrel is intended to beused. As shown more clearly in Fig. 2 at the forward end 7 of the barrel1 it is provided with a second bushing 8, non-rotatably received as atkey 9 and the outlet 20. Applied in snug face to face assembly betweenthe respective bushing 3 at the breach end and the bushing 8 at theforward end of the barrel respectively, the identical washers 10 havingthe form shown in plan in Fig. 5 are positioned. These washers arepreferably stamped with the rifling grooves 11 and the lands 12. Theouter grooves 13 are subsequently located in each washer periphery afterassembly, so that the lands '12 and grooves 11 form the desired riflingcontinuous extending transversely through each washer to form thegeneral configuration of rifling shown at 14 in Figs. 1

2,849,923 Patented Sept. 2, 1958 and 2. Initially, they are preferablyfitted upon a mandrel (not shown) suitably rifled to receive the washers10 and the slots 13 are then machined for the key 9.

In the modified from shown in Figs. 6 and 7, each of these washers 15 isalso identical in shape and preferably provided with the outer annularlyspaced projections 16 for engagement with similar spaced rifling grooves(not shown) within the gun barrel. Thus, this insures the properposition rotatively of each of the washers relative to each other toform the rifling desired. In this modification, each of the washerssnugly fits the rifled grooves of the gun barrel, the grooves of thebarrel having the same twist and spacing as the rifling desired. Thus,the washers when placed in the barrel rifled groove with the lugs 16engaging the barrel rifling will then be oriented so that the normalrifling will appear in the liner bore produced by the assembled washerswith only slight steps between each washer. It will, of course, beapparent that these washers may be stamped, if desired, so that theedges of the lands 14 will have a proper slope in each washer tominimize the sharp step arrangement normally formed by the corners 17 ofthe rifling grooves 18 and the lands 19.

It will also be apparent that the lands 19, the grooves 18 andprojections 16 may be formed on the modified washers 15 during thestamping operation.

In summary, it should be understood that the rifling in the assemblyliner washers is formed by properly orienting the washers relative toeach other either by assembling the Washers on an externally rifledmandrel (not shown) and then machining one or more straight longitudinalgrooves for keys 9 which mate with the corresponding grooves in thebarrel recess, or else each washer may be stamped with one or more lugs16 extending from the outer circumference and then completing theassembly with the gun barrel by cutting spiral grooves therewithinhaving the same twist as the rifling within the barrel recess. Thewashers are then inserted in the barrel recess so that the lugs engagethe spiral grooves with the washers in the desired position rotatively.

In considering this invention, it will, of course, be appreciated thatby means of such assembly, a composite liner has been provided having inaddition to other desirable properties great strength and yetsatisfactory ductility to resist the internal forces created by firingpressures. In the latter connection, it should be noted that it has beenfound that the longitudinal cracking of liners due to the exertion ofsuch forces are detrimental because erosion tends to localize in thecrack-ing formed and to wash out the liner material or the steel beneathit. Transverse cracks on the other hand can usually be tolerated.

While I have shown only two forms of the invention, it will be clearthat other forms may be used without departing from the spirit of theinvention as set forth in the appended claims.

I claim:

1. In a gun barrel and liner, the combination of a liner formed by theassembly of a plurality of washers in abutting face to face relation,the said washers being pre-rifled and having outer projecting portionsfor engagement with suitably formed interior surfaces of the saidbarrel, the inner peripheral edges of the washers being formed withgrooves and lands therebetween to create when assembled a rifled pathextending transversely continuously through each washer for aprojectile, and means cooperating with the barrel for retaining saidWashers in said face to face relation and in predetermined non-rotatableposition relative to each other.

2. In a gun barrel and liner, the combination of a liner comprising aplurality of pre-rifled washers assembled in abutting face to face'relation, the washers having outer portions for. engagement with: theinterior of the said barrel to hold the washers against relativerotation, inner peripheral surface portions of the washers beingrelieved to produce when assembled aztcontinuous interconnected rifledpath for a projectile,,the interior of saidwgun barrel also defining therelative rotativerpositionof the said" washers to. each other:

3. A-gun barrel andrliner combination, thelinenbeing comprisedofaplur-ality of pre-rifled washers vtransversely; extending inabuttingface to facerelation within. the.

barrel, the washers: having plain outer-surfaces with suitably formedportions guidedtby an interior portion of the. said. barrel, the 'inner'surfaces: of the Washers being formed with predeterminatelyrelievedportions .to pro? vide .when. assembled a continuous .rifiedpassage. for? a projectile, and means-cooperating withv the gun barrelto hold the said washerszagainstendmovement.

4'. A.-gun barrel and liner combination, theliner being formed with aplurality of pre-rifled:washers innabutting' face to face relation, thewashers having outer portions for engagement withtthe said vbarrel, theinner edgeszof the Washersbeing relieved to providetransverselyextending openings and forming when assembled a rifi'edpath for avprojectile, the gun barrel having, inner annularly,

jectile; the said gun barrel cooperating;;with1 said washersa to definethe extent of. said; rifled means: and rthe relative rotative positionof. said washers.

ReferencesnCited in the file.of=this patent UNITED STATES PATENTS1,544,469 Malaval June 30, 1925 2,499,944 Brace Mar. 7, 1950 FOREIGN'PATENTS 25,191 France .i1859,.'60'

